What were the effects of the importation of African slaves into the Americas?

The importation of slaves had different impacts on different groups. For example:

The slaves themselves were subjected to brutal conditions both while being imported and once in the Americas. Some places were worse than others, but all slaves ended up in a system that was fundamentally brutalizing.

African societies were devastated. They lost many people, most of whom were in the prime of life.

The whites in the places that received the slaves were hurt in at least a moral way. Slavery allowed them to treat other people like tools. This is not good for a person's sense of compassion or for their morality.

The American societies were forced to deal with (later in history) the consequences of slavery. Many of them have to deal with multi-racial societies in which there are still tensions between blacks and others.